Amplifiers with compensation

Abstract

An amplifier system includes a first amplifier, a second amplifier, a first capacitance, and a first transistor. The first amplifier has an input and an output. The second amplifier has an input that communicates with the output of the first amplifier. The first capacitance has one end that communicates with the input of the first amplifier. The first transistor has a control terminal, a first terminal that communicates with the output of the first amplifier, and a second terminal that communicates with another end of the first capacitance.

1. An amplifier system, comprising:
 a first amplifier having an input and an output; 
 a second amplifier having an input that communicates with said output of said first amplifier; 
 a first capacitance having one end that communicates with said input of said first amplifier; and 
 a first transistor having a control terminal, a first terminal that communicates with said output of said first amplifier and a second terminal that communicates with another end of said first capacitance. 
 
   
   
     2. The amplifier system of  claim 1  further comprising:
 a first current source that communicates with said second terminal of said first transistor. 
 
   
   
     3. The amplifier system of  claim 1  further comprising:
 a second current source that communicates with said first terminal of said first transistor. 
 
   
   
     4. The amplifier system of  claim 1  further comprising:
 a first current source that communicates with said second terminal of said first transistor; and 
 a second current source that communicates with said first terminal of said first transistor. 
 
   
   
     5. The amplifier system of  claim 1  wherein said first and second amplifiers include operational transconductance amplifiers. 
   
   
     6. The amplifier system of  claim 1  wherein said first and second amplifiers include operational amplifiers. 
   
   
     7. An amplifier system, comprising:
 a first amplifier having an input and an output; 
 a second amplifier having an input that communicates with said output of said first amplifier; 
 a first capacitance having one end that communicates with said input of said first amplifier; 
 a second capacitance having one end that communicates with said input of said second amplifier; and 
 a first transistor having a control terminal, a first terminal that communicates with another end of said second capacitance and a second terminal that communicates with another end of said first capacitance. 
 
   
   
     8. The amplifier system of  claim 7  further comprising:
 a first current source that communicates with said second terminal of said first transistor. 
 
   
   
     9. The amplifier system of  claim 7  further comprising:
 a second current source that communicates with said input of said second amplifier. 
 
   
   
     10. The amplifier system of  claim 7  further comprising:
 a first current source that communicates with said second terminal of said first transistor; and 
 a second current source that communicates with said input of said second amplifier. 
 
   
   
     11. The amplifier system of  claim 7  wherein said first and second amplifiers include operational transconductance amplifiers. 
   
   
     12. The amplifier system of  claim 7  wherein said first and second amplifiers include operational amplifiers. 
   
   
     13. An amplifier system, comprising:
 first amplifying means for amplifying having an input and an output; 
 second amplifying means for amplifying having an input for communicating with said output of said first amplifying means; 
 first capacitance means for providing capacitance having one end for communicating with said input of said first amplifying means; and 
 a first transistor having a control terminal, a first terminal for communicating with said output of said first amplifying means and a second terminal for communicating with another end of said first capacitance means. 
 
   
   
     14. The amplifier system of  claim 13  further comprising:
 first current source means for providing current and for communicating with said second terminal of said first transistor. 
 
   
   
     15. The amplifier system of  claim 13  further comprising:
 second current source means for providing current and for communicating with said first terminal of said first transistor. 
 
   
   
     16. The amplifier system of  claim 13  further comprising:
 first current source means for providing current and for communicating with said second terminal of said first transistor; and 
 second current source means for providing current and for communicating with said first terminal of said first transistor. 
 
   
   
     17. The amplifier system of  claim 13  wherein said first and second amplifying means include operational transconductance amplifiers. 
   
   
     18. The amplifier system of  claim 13  wherein said first and second amplifying means include operational amplifiers. 
   
   
     19. An amplifier system, comprising:
 first amplifying means for amplifying having an input and an output; 
 second amplifying means for amplifying having an input that communicates with said output of said first amplifying means; 
 first capacitance means for providing capacitance having one end for communicating with said input of said first amplifying means; 
 second capacitance means for providing capacitance having one end for communicating with said input of said second amplifying means; and 
 a first transistor having a control terminal, a first terminal for communicating with another end of said second capacitance means and a second terminal for communicating with another end of said first capacitance means. 
 
   
   
     20. The amplifier system of  claim 19  further comprising:
 first current source means for providing current and for communicating with said second terminal of said first transistor. 
 
   
   
     21. The amplifier system of  claim 19  further comprising:
 second current source means for providing current and for communicating with said input of said second amplifying means. 
 
   
   
     22. The amplifier system of  claim 19  further comprising:
 first current source means for providing current and for communicating with said second terminal of said first transistor; and 
 second current source means for providing current and for communicating with said input of said second amplifier. 
 
   
   
     23. The amplifier system of  claim 19  wherein said first and second amplifying means include operational transconductance amplifiers. 
   
   
     24. The amplifier system of  claim 19  wherein said first and second amplifying means include operational amplifiers. 
   
   
     25. The amplifier system of  claim 19  further comprising:
 first resistance means for providing resistance having one end that communicates with said first terminal of said first capacitance means and another end that communicates with a voltage reference; and 
 first current supply means for supplying current that communicates with said second terminal of said first transistor. 
 
   
   
     26. The amplifier system of  claim 19  further comprising:
 first current supply means for supplying current that communicates with said first terminal of said first capacitance means and with a voltage reference; and 
 first resistance means for providing resistance that communicates with said second terminal of said first transistor. 
 
   
   
     27. The amplifier system of  claim 7  further comprising:
 a first resistance having one end that communicates with said first terminal of said first capacitance and another end that communicates with a voltage reference; and 
 a first current source that communicates with said second terminal of said first transistor. 
 
   
   
     28. The amplifier system of  claim 7  further comprising:
 a first current source that communicates with said first terminal of said first capacitance and with a voltage reference; and 
 a first resistance that communicates with said second terminal of said first transistor.